As electrophotographic developers, a dry developer in which toner components composed of materials containing a colorant and a resin binder are used in a dry state, and a liquid developer in which toner components are dispersed in an insulating liquid have been known.
In a liquid developer, toner particles are dispersed in oil in an insulating liquid, thereby making it possible to form smaller particle sizes as compared to a dry developer. Therefore, high-quality printouts can be obtained surpassing offset printing, so that the liquid developer is suitable for commercial printing applications.
Patent Publication 1 discloses a liquid developer containing at least toner particles, a carrier liquid, and a dispersant, characterized in that the dispersant comprises a succinic acid imide compound and a fluorine-containing silane compound.
Patent Publication 2 discloses a liquid toner dispersion provided with marking particles comprising a pigment, and a polyester-based resin such as a polyester-based resin, the dispersion comprising a nonpolar organic carrier liquid and a hyper-dispersant comprising a graft copolymer provided with an anchor group comprising an amine-functionalized polymer onto which stabilizing groups are grafted, which anchor group is anchored on a surface of a marking particle, wherein a first stabilizing group and a second stabilizing group are grafted to the anchor group, wherein the first stabilizing group is a fatty acid compound and the second stabilizing group is a polyolefin.
Patent Publication 1: Japanese Patent Laid-Open No. 2011-027845
Patent Publication 2: Japanese Patent Laid-Open No. 2015-135475